The CSHKP model ([1]}; [2]}; [3]}; [4]}) and its extension in three-dimensions ([5]}; [6]}; [7]}) can explain several observational signatures of the fully (or failed) eruptive flares, such as the presence of X-ray sigmoids, flare ribbons, and brightening motions along the ribbons themselves. In particular, [8]}, [9]} have shown that the flare ribbons often coincide with the photospheric signature of quasi-separatrix layers [10]}, i.e., thin layers characterized by a sharp gradient in the connectivity of the magnetic field. The brightening motions along the ribbons have been interpreted as the signatures of the slipping reconnection of the magnetic field lines through the QSL ([11]}; [6]}; [13]}). High resolution observations and interpretation of the slipping motion of plasma material in the AR are required to explain the magnetic behaviour of the region ([14]}; [15]}).
